Need wifi calling on a 10.2 leak?

I have a STL001 Z10 running the 10.2.0.147 leak. and i LOVE it. Every single feautre and improvement brought by the 10.2 leak is something I can't live without.
However, I am on TMOBILE and would like to take advantage of the new Wifi calling. What course of action can I take to get this on my phone? If a downgrade is involved, I would like to preserve my data and settings.

You can flash the .810 or .811 radio and sideload the TMo app to control the wifi calling, but sometimes the app gets wonky, you may get error messages when sending texts, and some folks have echos on calls.

I'm running 10.2.0.1047 with. 810 radio on t-mobile.
I have the latest t-mobile wifi calling app.
It does work but it is a little buggy. If I am somewhere that I need the wifi calling, I can use the app to switch it on, then restart the phone and it works..
When I don't need it, I use the app to switch it off, then restart the phone. That's been the best method of using it.

Sometimes I get a reg99 error when connecting but it goes away after a few minutes.